AntennasPosted by Sean Gilbert Mon, February 21, 2011 09:59:15
Well it's been quite a time since I last posted, due to the pressures of work. However, after all the winter snow and very cold weather (down to -13C at times) I thought it was a good idea to service the antennas. At the same time I put up a new antenna - a dedicated 6m sloper.
The OCF was picking up more noise than I would have liked, I was not sure if this was due to the ingress of moisture or something else antenna related or whether it was an increase in background EMC levels. As it turns out, I think it was the EMC levels that increased. Upon checking the antenna I was pleased to see that all the joints had remained watertight and there was no evidence of corrosion. I wanted to upgrade the ferrite choke so the coax plug was replaced anyway. The original choke consisted of 7 turns wound over 3 ferrite rings. The improved version has 7 turns over a stake of 5 rings. This did improve the performance, but the noise also increased (due to the vertical radiating part of the antenna becoming more effective). This was not what I wanted, I was trying to reduce noise! Also the choke was much heavier than before so was putting stress on the coax and the PL259 connector. With this in mind I moved the choke from 10 feet below the feedpoint to directly under the feedpoint and used cable ties to secure it to the balun box, giving strain relief to the feeder.
This changed the resonance, obviously, but it did help with the noise pickup, some bands in particular are much better than they were. Also the 6m sloper seems to work well and provides much better signals than the OCF on my local beacons, plus it is quieter on receive.
I have put pictures and info about these antennas on my website.
Now I am waiting for the 6m sporadic E season to start!!
DX heard/workedPosted by Sean Gilbert Wed, October 06, 2010 22:18:01
Interesting day today (6 Oct), found a few minutes to review what I had heard on the radio and discovered that I had heard all 6 continents (for radio purposes Antarctica doesn't count) on 15m PSK31 in just 40 minutes.
This is the PSK reporter log for the period (with other entries removed):
SA: LU4LA 15m PSK31 10740 kms 13:59:03
OC: YC1DML 15m PSK31 11896 kms 13:57:03
EU: UA6ASU 15m PSK31 2976 kms 13:55:19
AS: 5B4AIK 15m PSK31 3300 kms 13:55:01
AF: ZS2DK 15m PSK31 9917 kms 13:45:54
NA: AB3LH 15m PSK31 3499 miles 13:19:56
I have no idea why the last (NA) one shows up in miles!
Quite impressive considering everyone is bemoaning the lack of sunspots. I have found that 15m has been wide open to JA and South America most days.
Digimode happeningsPosted by Sean Gilbert Mon, August 30, 2010 08:43:52
I have just been going through the WSPR archives for my callsign, and have discovered that I have been heard by well over 500 stations - 500 is the limit for displaying entries, even though you can display entries going back as far as you like. I decided to display the maximum 500 entries but sorted by distance, showing the longest first. I was surprised to see that my little 5 watt signal has been heard by a total of 198 stations with a minimum distance of 4000km. 22 of these stations were over 10000km, with the furthest being 18934km (in fact 5 of those were over 18000km distant). Just yesterday I was being received on the west Coast of the USA whilst running 5w but, more amazingly, I was hearing that West Coast station who was running a mere 0.5w (over 15000km per watt!). I think he could have reduced by another 3dB and I would have still copied him, possibly even another 6dB
Here are the furthest stations that have heard my WSPR signals (notice the spread of frequencies):
Band Call QRA km
I am impressed by this, hopefully as more stations become active, the better picture of propagation we will get. There are usually around 70-90 stations active on 30m and 20m but more are needed, especially on the other bands. I try to operate on 40, 17 and 15m when conditions allow (and even 10m, but this is limited to Sporadic E at the moment so is not really useful for long distance propagation studies).
Digimode happeningsPosted by Sean Gilbert Wed, August 25, 2010 11:15:57
Here is the 2nd part of the WSPR session from 24th August on 20m. In the end I stuck with 20m until I closed down at around 2200 UTC. Propagation was quite good, with long openings to the USA. Below is the complete list of stations that heard me yesterday, arranged by distance. From the list I can see there are 19 stations over 5000km away which I am pleased with. Furthest distance was just short of 17000km, right down in the Australian Capital Territory (or ACT as it is known). Trying with 2 watts will be interesting and is something I will try later in the year (I would think that with the better propagation of the winter, there won't be much difference between 2w and the 5 watts I was using for this session.
I will repeat this experiment from time to time to see how propagation changes.
Digimode happeningsPosted by Sean Gilbert Tue, August 24, 2010 17:44:11
I decided to have a WSPR session this afternoon, mainly to test the station (making sure that all the various software programs work now that I am using a different computer - getting them all to co-operate has been quite difficult).
The table shows unique stations (i.e. no duplicates), and the results are quite interesting:
Best DX is 9520km (Japan), not bad as I am only running 5 watts.
Other notable stations that heard my signals were from both the East and West Coasts of the USA, Manitoba in Canada, India and Venezuela.
UTC QRG SNR dt My QRA Pwr Callsign DX QRA km
15:54 14.097110 -17 0 IO92ma 5 4X1RF KM72ls 3586
15:54 14.097129 -14 0 IO92ma 5 I53CASWL JM49nf 1621
15:54 14.097118 -23 0 IO92ma 5 JF3MKC PM74xm 9520
15:54 14.097133 -26 0 IO92ma 5 KO6SY DM14kb 8616
15:38 14.097118 -22 -1 IO92ma 5 LA3JJ JO59bh 1065
15:32 14.097094 -25 0 IO92ma 5 VE4SIG EN19ku 6221
15:02 14.097121 -23 0 IO92ma 5 W5CGC EM12kx 7568
14:48 14.097131 -28 0 IO92ma 5 VU2LID MJ88lm 8436
14:46 14.097070 -2 1 IO92ma 5 UA3ARC KO85so 2525
14:44 14.097084 -23 -1 IO92ma 5 DJ3VI JO43vi 739
14:44 14.097108 -26 0 IO92ma 5 W3GXT FM19ol 5768
14:44 14.097126 -27 0 IO92ma 5 OE5VLL JN78fc 1181
14:26 14.097116 -8 -1 IO92ma 5 LA6TPA JP54rl 1558
14:26 14.097137 -25 0 IO92ma 5 OH5MD KP20ng 1840
14:22 14.097084 -27 0 IO92ma 5 YV4GJN FK50xf 7553
14:18 14.097118 -23 0 IO92ma 5 NB3N FM19ki 5799
14:10 14.097116 -17 0 IO92ma 5 N4AU EM62vp 6904
The map shows WSPR signals both TX and RX heard on 20m this afternoon.
I am going to leave WSPR running all evening, probably on 20m but I may change to 30 or 40m later on if conditions look promising on the lower bands (there have been a lot of QRN/static crashes on the low bands over the past few days, making reception a bit hit and miss).
Digimode happeningsPosted by Sean Gilbert Tue, August 24, 2010 16:37:14
Well no sooner had I posted the set of frequencies that I found on the ROS site, did they go and change them, again! There have been at least 6 changes just in August (in fact there could well have been more I didn't check too closely earlier in the month as I was arguing with a reluctant laptop!)
So here are the latest offerings (Changes to the last list are marked in bold):
One thing I have noticed is the bandwidth has apparently reduced from 2250Hz down to 2000Hz/2kHz, which can only be a good thing.
ROS QRG's (Aug 2010)
7048kHz 500Hz - NEW
10145kHz 500Hz - NEW
14079kHz 500Hz - NEW (ex 14091kHz)
18114kHz 2000Hz - NEW
21114kHz 2000Hz - NEW
70074kHz 2000Hz - NEW
Here is a screen grab of the PSKReporter screen, seems I was heard in a few places when I ran my ROS beacon yesterday. I received a few email reports detailing my signal strength etc. in a few countries. Still enjoying playing about with the mode.
DX heard/workedPosted by Sean Gilbert Mon, August 23, 2010 15:40:11
Well I must admit to being rather surprised yesterday at hearing KH7DX
on 20m PSK31. I've heard Hawaii a number of times this year but not on PSK. What I didn't realise until I checked my log statistics (as I do regularly when I update the totals on my website) is that the KH7 gave me WAZ (Worked All Zones - or in my case HEARD All Zones) for the year. PSK is the first single mode I have achieved this on so far this year. Out of the possible 40 CQ zones, I have heard 38 on SSB, 39 on CW and 40 on PSK, with 29 on RTTY. The only band I have WAZ on is 20m, but 40m, 30m, 17m and 15m are all in the low 30's so there is a possibility I could get near to WAZ on some of those.
Looking at the overall DXCC score for the year, this is turning out to be one of the better years with 216 so far. Since 1996 only 2004 (244) and 2005 (239) have had a greater score - and that was at the peak of the sunspot cycle. 2010 is pretty much at the bottom of the cycle, we are just entering the new cycle but it will be a few years before we are at the peak again. Last years score was 205 and I have beaten every band total for last year. This I put down to the antenna. Propagation conditions have been fairly poor and probably quite comparable to last year. The QTH and rig are the same, the only thing that has changed noticeably is the antenna system. I have gone from using a half G5RV which did not present a low SWR on any band, to an Off Centre Fed Dipole (which I have made into a Carolina Windom by inserting a common mode choke on the coax 10 feet from the feedpoint). I spent some time tuning this antenna for the configuration it was to be used in (which is not, as it should be, a standard straight run of 66 feet). I can run this on 40, 20, 17 and 10m without an ATU (in fact I can run it on 12 and 6m if needs be as the SWR is below 3 on both bands). The worst bands are 30 and 15m, but even then it tunes OK with the internal ATU.
I am toying with the idea of improving the 'line isolator' as I'm not convinced that the 6 turns over 3 rings is giving a high enough impedance to electrically 'disconnect' the coax above it. Of course the other part of me is saying that 'if it ain't broke, don't fix it'! That part will probably win as I have no idea what would happen to resonance if I start to fiddle with other parts of the antenna.
I'm going all out to see how close I can get to my scores during the last solar peak. 3 1/2 months of the year left, with a couple of the biggest contests to boot so there is opportunity (just need operating time and a good slice of luck)
Digimode happeningsPosted by Sean Gilbert Tue, August 17, 2010 12:36:23
There has been an incredible amount of stuff written about ROS both good and bad. One thing that crops up time after time is the subject of which frequencies to use. Here is the latest list (as of today), taken from v5.0 of the ROS software. The first column denotes the suggested frequency and the second column is the mode or bandwidth to use. I would like to see options to use 500Hz on all bands, especially on 40 and 12m. The fact that there are now no less than 5 spot frequencies on 20m is likely to raise some eyebrows. Although ROS seems to work reasonably well, to my mind it is still not as good as some of the narrower band modes. The other thing that I find disconcerting is that there is an awful lot of pre-amble and 'aft-amble', when you hit the ptt button to stop the transmission a good 5-10 seconds pass before the tones stop and you are returned to receive (even if all the text in the box has been sent). I have just discovered that you can't change mode on some bands (like 15m, you are stuck on 2250Hz whether you like it or not, the only way out is to turn off CAT and change band to, say, 20m where certain frequencies allow 500Hz. Not a very flexible system and does not allow for easy experimentation. Using 2250Hz for all transmissions is not spectrum efficient! That said I am still using the mode and just adapting it to my own preferences as much as possible. Any way, here are the latest frequencies:
QRG's (Aug 2010)
15m (21110) has been quite busy, and I am seeing a lot of spots on the dxcluster (this is another area that is causing some bad press as it is generating a lot of spots because of it's autospotting routine).
You can download the latest version of ROS from the homepage: http://rosmodem.wordpress.com/
Digimode happeningsPosted by Sean Gilbert Wed, August 04, 2010 15:41:02
Despite the poor conditions due to the CME, there is still some dx to be had on JT65. This afternoons haul on 20m includes JA6CRP
(Japan, weak at -23dB but solid copy), 9H1BT
(Malta, A new station for me on this mode), DS1DLS
(Korea, also weak at -24dB, about the same time as yesterday) and a scattering of European and Eu Russian stations.
I have not seen a single signal from the USA so far today, which is unusual. It's 1430UTC so they should be audible by now as the whole of the USA is well into daylight, the exceptions being the Hawaiian islands and the far West tip of Alaska, both of which are in the greyline area but the lower 48 states and all of Canada are in broad daylight.
I am going to put out a few calls on JT65 and see where I am being heard (by checking the 'reverse beacon' page (http://jt65.w6cqz.org/receptions.php), this allows you to filter results and you can see who is hearing you - there are usually a good selection of stations monitoring and it is a great way to see if a path exists between you and your desired area (providing of course there are monitors active there!).
It's stopped raining here and the background noise level has dropped. This is also helped by the fact that there are no other computers or TV's on here and the neighbours are out so electrically it is fairly quiet too.
Note to self: Next time you buy a TV make sure it does not have a plasma screen, boy do they radiate some rubbish. I wouldn't mind but it was a top of the range one by a well respected manufacturer!! Thus far I have not found a solution, other than to minimise it with the MFJ1026 as detailed on my website.
Better go and enjoy the quiet while it lasts, as I'm sure it will start raining again soon.
General ramblingsPosted by Sean Gilbert Wed, August 04, 2010 11:39:13
Here is the news from "DX.QSL.NET" concerning the solar flare/CME that was reported in the press yesterday (I found out about this from the news pages on Google!). It remains to be seen how much of an impact this has on the HF bands. The upper bands are fairly quiet but the background noise level is higher than normal - also it's raining quite heavily so I am probably getting some rain static adding to the overall background. A quick check on 6 and 10m didn't reveal any auroral activity. These events will get more common as the sun becomes more active over the next few years.
I don't particularly like these events as they knock out the high bands plus increase the background noise level masking any weak signals (and tend not to be strong enough to produce Au), plus the absorption on the lower bands is much higher than normal, making those all but useless. This means that the majority of traffic is concentrated on 20m and can make it rather congested. These events usually coincide with the times I do work on the equipment/antennas (not on purpose of course) and when I switch on after completing the work I often hear reduced strength signals with increased noise, which tends to make me panic slightly, although now I check the propagation forecast to see if anything has happened (and I make notes of signals heard before I do the work - which is not foolproof of course as a radio blackout could happen when the radio is off during the course of maintenance work!)
News from http://dx.qsl.net/propagation/index.html
Geomagnetic field activity is expected to be at unsettled to minor storm levels on day 1 (04 August) as the current CME passage continues. Activity is forecast to increase to active to minor storm levels with a chance for major storm levels on day 2 (05 August) due to the arrival of the halo-CME observed on 01 August (associated with a large filament disappearance). Activity is expected to decrease to unsettled to active levels on day 3 (06 August) as CME effects subside.
Here are the figures from the DK0WCY propagation beacon in Kiel, Germany:
Date Hour SFI A K Exp.K R SA GMF Aurora Logger
3-Aug-2010 23 79 6 5 5 17 qui act no <DK0WCY>
3-Aug-2010 22 79 6 5 4 17 qui act no <DK0WCY>
3-Aug-2010 21 79 6 5 2 17 qui act no <DK0WCY>
3-Aug-2010 20 79 6 4 4 17 qui act no <DK0WCY>
3-Aug-2010 19 79 6 4 4 17 qui act no <DK0WCY>
3-Aug-2010 18 79 6 4 3 17 qui act no <DK0WCY>
3-Aug-2010 17 79 6 2 2 17 qui act no <DK0WCY>
3-Aug-2010 16 79 6 2 1 17 qui act no <DK0WCY>
3-Aug-2010 15 79 6 2 0 17 qui act no <DK0WCY>
3-Aug-2010 14 79 6 3 2 17 qui act no <DK0WCY>
And these are the latest figures from WWV:
Date Hour SFI A K Forecast
4-Aug-2010 09 81 16 3 Moderate w/G2 -> Minor w/G1
4-Aug-2010 06 81 16 4 Moderate w/G2 -> Minor w/G1
4-Aug-2010 03 81 16 6 Moderate w/G2 -> Minor w/G1
4-Aug-2010 00 81 16 5 Minor w/G1 -> Minor w/G1
3-Aug-2010 21 81 16 4 No Storms -> Minor w/G1
The 'K' index rose to 6 (9 is the highest and indicates extremely disturbed conditions), which is the highest it has been for quite a long time. It iwll be interesting to see how things pan out over the next few days. I think it safe to say that MW and 160m will not be open for DX until these figures settle down to much lower numbers (ideally both A and K should be at 0)!